June 1944 QST
of Contents]These articles are scanned and OCRed from old editions of the
ARRL's QST magazine. Here is a list of the
QST articles I have already posted. All copyrights (if any) are hereby acknowledged.
was the name given to early walkie-talkies used in the field by military
communications troops. Having been written during World War II, the
author of this QST article just assumed that any reader would be familiar
with the WERS acronym - it stands for
War Emergency Radio Service
. Per the Wikipedia entry: "At the
start of the Second World War the United States Congress had suspended
all amateur radio activity throughout the country. WERS was established
by the Federal Communications Commission in June 1942 at the insistence
of the American Radio Relay League. WERS would remain in operation in
through the end of the Second World War in 1945. WERS was to provide
communications in connection with air raid protection, and communications
during times of natural disaster. WERS licenses were given to communities
and not individuals. One of the requirements for individuals to participate
in the WERS was to hold an Amateur radio license."
A Self-Contained Handie-Talkie
A Compact Light-Weight WERS Unit Operating from Dry Batteries
By Charles T. Haist. Jr., W6TWL. EX-W9EQL
application of units of the handie-talkie type to WERS work is very
practical in that they may be operated right at the scenes of incidents
or disaster, leaving the operator free to walk or move around and still
have one hand available to assist in other duties. Such low-power units
are intended primarily to be used in conjunction with a higher-powered
mobile unit which may be located several blocks away, parked in a favorable
spot which permits satisfactory communication with the control center
for the purpose of relaying messages.
When necessary, however,
surprising distances can be covered with handie-talkie units when they
are operated in the clear. Communications with control center KMFY-1,
with a signal report of R4/S4 at distances up to ten miles, have been
accomplished with the hand-portable shown in the photographs. R5/S5
reports have been logged at distances of up to three or four miles.
This unit is built along the lines of some of those used by
the armed forces. The complete transceiver and its battery power supply,
enclosed in an aluminum case as shown, weighs but 3 7/8 pounds. The
outside dimensions of the case are only 2 5/8 X 2 3/4 X 11 inches.
The transceiver circuit,
shown in Fig. 1, is more or less conventional in most respects. It was
drawn up around the type 1S4 tube, which is the secret of the set's
Two tubes of this type are used in the unit. One,
with its screen tied to the plate, is used as a triode oscillator and
detector. The other 1S4 is used as an audio amplifier and modulator.
Many have encountered trouble in getting the 1S4 to super-regenerate
on frequencies as high as 112 Mc. In this circuit this difficulty was
solved by placing a 0.005-μfd. condenser, C3, across the receiving grid
* 750 Warfield Ave., Oakland 10, Calif.
The microphone is insulated from the aluminum case so that it may
be connected in series with the single headphone, P, for side-tone transmitting.
The headphone, which has an impedance of about 100 ohms, was provided
with an output transformer, T1
, for proper impedance matching
to the output of the 1S4. When transmitting, the secondary is opened
and the primary is used as a Heising modulation choke.
for the audio amplifier or modulator is provided by operating the "B"
- below ground potential and using the voltage drop across R1
Regeneration is controlled by a simple variable series resistance, R4
in the "B" + lead to the detector so that an additional switch
is not necessary to eliminate battery drain when the set is turned off.
The change-over switch, S1
, is a four-pole triple-throw
rotary switch. In addition to the two usual positions, a third position,
labeled 0 in Fig. 1, is provided where all battery circuits are open.
The filament circuit is completed when the switch is placed in either
the receiving or the transmitting position.
The filament battery
consists of two No. 3 flashlight cells connected in parallel for longer
life. They are held in the case by spring clips. The plate battery is
a 67 1/2-volt Minimax or two 45-volt hearing-aid batteries in series.
These batteries are not too difficult to buy now, since stores are selling
them on the open market after the nominal installation date has passed.
One penlite cell provides adequate voltage for the microphone.
The case for the unit is made
of pieces of sheet aluminum fastened together with self-tapping screws.
The metal was given a "swirl" finish by applying a spinning
cork, held in the chuck of a drill press, after the aluminum sheet had
been smeared with a thin coating of a mixture of valve-grinding compound
The microphone, mounted in the lower end of the panel,
and the single headphone at the top are from a Western Electric handset
in which the brass threads moulded in the handle were cut off with a
hacksaw to provide mountings. The regeneration control is on the right
side and the change-over switch on the left side in a position convenient
for one-hand operation.
These two views of W6TWL's hand-portable
transceiver show the arrangement of controls. The left-side view shows
the headphone. microphone, and, on the side. the change-over switch.
The right-side view shows the regeneration control on the side and the
tuning knob and scale on the rear.
The batteries occupy the
lower section of the case, the "A" battery cells being mounted
in clips at the bottom and the "B" battery immediately above.
The penlite microphone battery is mounted in a clip on top of the headphone
The transceiver components consume the remaining
space at the top. The r.f. tube is mounted in an inverted position in
a polystyrene socket, while the audio tube socket is fastened to a shelf
at the left in the inside view of the unit. The tank coil, L2
is soldered directly to the terminals of the tuning condenser, C5
which is mounted immediately below the antenna terminal.
antenna is a quarter-wave rod, 24 inches long, which plugs into a receptacle
on top of the case. It is coupled to the tank coil by a single turn
of wire, L1
, one end of which is grounded to the case. With
this arrangement transmission and reception seem to be good even with
the antenna at an angle or in a horizontal position.
has seen considerable successful service during the past few months.
The life of the batteries is very good despite their small size, since
the current drain on the filament battery is only 200 ma. and the total "B"
battery current is only 10 ma. when receiving and 15 ma. when transmitting.
The handie-talkie unit with the front cover removed. The miniature
plate and filament batteries occupy the lower portion of the case, while
the r.f. and audio components are fitted into the top section.
A Self-Contained Handie-Talkie Schematic
Fig. 1 - Circuit diagram of W6TWL's hand-portable WERS station.
- 0.001-μfd. midget mica.
0.003-μfd. midget mica.
- 0.005-μfd. midget mica.
- 50-μfd. midget mica.
- 750 ohms, 1/2-watt carbon.
- 25,000 ohms, 1/2-watt carbon.
megohms, 1/2-watt carbon.
- 100,000-ohm potentiometer
- 1 turn No. 12, 1/2-inch
- 4 turns No. 12, 1/2-inch inside
- V.h.f. r.f. choke (Ohmite Z-0 or homemade
M - Single-button carbon microphone (see text).
P - Single headphone, 100 ohms (see text).
three-position rotary switch.
-8000- to 100-ohm output
- Transceiver transformer.